DC1144A-B: -12V @ 350mA, 5 ~ 12V in, Inverting


Demonstration circuits 1144A-A and 1144A-B feature the LT3580EDD in Boost/Inverting Regulator configurations. The demo circuits demonstrate small size and low component count. The boost is designed to convert a 3 – 10 V source to 12 V at 300 mA while the inverter converts a 5 – 12 V source to -12 V at 350 mA. Both converters use only one feedback resistor to set the output voltage.

The LT3580 operates with inputs as high as 32 V but in these demo boards the input is limited by the voltage rating of the input capacitors and the magnitude of the boost output. In a boost converter the input needs to be less than the output.

Care must be taken when operating the LT3580 at high input voltages as the junction temperature increases due to higher internal dissipation. Higher switching frequencies also increase the internal dissipation.

The LT3580 gets powered from the main input in both, DC1144A-A and DC1144A-B, but there is an option for a linear regulator built into the board that will allow the IC to be powered from a lower voltage. If this option is used, just cut the trace as shown in figure 6 and install the optional emitter follower on the back of the board.

The DC1144A-B can easily be configured into a SEPIC converter, just switch the positions of L2 and D2 as shown in figure 6.

The LT3580 includes many other features such as synchronization to external clock, user configurable undervoltage lockout, soft-start, frequency foldback, and it is easily as a boost or inverter converter.

These circuits are intended for space-conscious applications such as local bus supplies, TFT-LCD bias supplies, GPS receivers, VFD bias supplies, and DSL modems.


Manufacturer Analog Devices Inc.
Category AC/DC and DC/DC Conversion
Sub-Category DC/DC SMPS - Single Output
Eval Board Part Number DC1144A-B-ND
Eval Board Supplier Analog Devices Inc.
Eval Board Normally In Stock
Topology Inverting
Outputs and Type 1 Non-Isolated
Voltage Out: Factory Set -12 V
Current Out 350 mA
Voltage In 5 ~ 12 V
Efficiency @ Conditions >80%, 5V in, -12V @ 108 ~ 340 mA
Voltage Out Range -11.64 ~ -12.36 V
Features Current Limit (Adj. or Fixed)
Shutdown, Enable, Standby
Soft Start
Under Voltage Protection, Brown-Out
Switching Frequency 200 kHz ~ 2.5 MHz
Standby Current [Typical] 0 µA
Quiescent Current [Typical] 1 mA
Component Count + Extras 20 + 8
Internal Switch Yes
Design Author Linear Technology
Application / Target Market GPS
LCD and OLED Bias Supplies
Point of Load (PoL)
Standby Current [Maximum] 1 µA
Quiescent Current [Maximum] 1.5 mA
Main I.C. Base Part LT3580
Date Created By Author 2006-08
Date Added To Library 2015-07

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